Introduction

In this blog post, we will explore how to solve the LeetCode problem "3370" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

You are given a positive number n. Return the smallest number x greater than or equal to n, such that the binary representation of x contains only set bits Example 1: Input: n = 5 Output: 7 Explanation: The binary representation of 7 is "111". Example 2: Input: n = 10 Output: 15 Explanation: The binary representation of 15 is "1111". Example 3: Input: n = 3 Output: 3 Explanation: The binary representation of 3 is "11". Constraints: 1 <= n <= 1000

Explanation

Here's the breakdown of the solution:

• Find the Most Significant Bit: Determine the position of the most significant bit (MSB) in the binary representation of the input number n.
• Create a Mask: Construct a number that has all bits set from the least significant bit up to the MSB position. This effectively creates a number with all 1s in its binary representation up to the required length.

• Return the Mask: The mask itself is the smallest number greater than or equal to n with all set bits.

• Runtime Complexity: O(log n) - due to finding the MSB. Storage Complexity: O(1) - constant extra space.

Code

    def solve():
    n = int(input())

    msb = 0
    temp = n
    while temp > 0:
        temp >>= 1
        msb += 1

    result = (1 << msb) - 1
    print(result)

solve()